Resumo

A V-grooved, origami surface may be used to control apparent emissivity and absorptivity dynamically
through control of the cavity effect with linear actuation. However, for a fixed material size, the projected surface area decreases as the apparent emissivity increases. A model was developed to examine the total emission of a V-grooved surface as a function of cavity angle for both diffuse and collimated irradiation. The maximum rate of net radiative heat exchange exists at a cavity angle of 180° (unfolded) for diffuse
irradiation and at or above 120° for collimated irradiation at any intrinsic emissivity value. The net radiative heat exchange for diffuse irradiation increases monotonically with increasing cavity angle; collimated
irradiation normal to the projected area results in a general increase in net radiative heat exchange with
increasing cavity angle but with local minimums observed at some cavity angles due to a finite, whole
number of reflections. Experimental data to indicate the ability to control surface temperature with cavity
angle was also collected using a vacuum chamber and Joule heating of a folded surface.